Bearings such as axial bearings and radial bearings are used, for example, for supporting a shaft in a housing. In this case, an insufficient heat dissipation via the bearing sleeve may, for example, limit the use of permanent magnets and/or bindings in the rotor area of an electric motor. Furthermore, heat-related changes in length may result in asymmetries and a distortion in the bearing support.
Heat sinks are often used for heat dissipation. However, so that an adequate heat dissipation may occur via such heat sinks, they must be in direct contact with, for example, the bearing sleeve, the press-fit normally used for this resulting in a mechanical stress of the bearing sleeve.
For example, a cooling system for a gear unit is described in German Patent Application No. DE 10 2008 017 755 A1, which includes a heat sink, having a passage bore for passing a shaft through, and cooling ribs extending from the heat sink in the radial direction. This heat sink rotates with the shaft, an additional cooling effect being obtained from an air turbulence resulting from the movement of the heat sink or the ribs.
It is very difficult to use such a heat sink in a confined space, in particular within a housing of an electric motor or, for example, a compressor. Furthermore, an adequate supply of fresh air is required. It is difficult to implement additional cooling with the aid of a cooling liquid.
An object of the present invention is to provide a possibility for cooling a bearing sleeve, in particular with the aid of fluid cooling, which makes effective heat dissipation possible, requires little space, and keeps the mechanical stress of the bearing sleeve at a low level.
This objective may be achieved by a cooling sleeve in accordance with example embodiments of the present invention.